Monthly Archives: September 2015

When X+0 and X-0 are not the same

Oren Nakdimon Leave a Reply

In the old days, when the Rule Based Optimizer (RBO) ruled, there was a very common technique to help the optimizer choose one plan over the other (if they had the same rank) by preventing the use of an index. Look at the following query, where there are unique indexes on T1.ID and T2.ID and […]

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Split

Oren Nakdimon Leave a Reply

Here is a small pipelined table function that gets one string that includes a delimited list of values, and returns these values as a table: create or replace function split (i_str in varchar2, i_delimiter in varchar2 default ‘,’)   return sys.odcivarchar2list   pipelined   as     l_current_string varchar2(4000) := i_str;     l_pos            binary_integer;   begin […]

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